cmd = connection.CreateCommand();
                            cmd.CommandType = CommandType.Text;
                            cmd.CommandText = "UPDATE UTENTI SET credito_residuo = credito_residuo + " + ricarica + ",credito_acquistato = credito_acquistato+ " + ricarica + "WHERE id_utente = " + id_utente;
                            connection.Open();
                            int count = cmd.ExecuteNonQuery();
                            connection.Close();